How do I convert a long to a string in C

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boost  lexical cast lt std  string gt  my long  more here http   www boost org doc libs 1 39 0 libs conversion lexical cast htm

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I don t know what kind of homework this is  but most probably the teacher doesn t want an answer where you just call a  magical  existing function  even though that s the recommended way to do it   but he wants to see if you can implement this by your own   Back in the days  my teacher used to say something like  I want to see if you can program by yourself  not if you can find it in the system   Well  how wrong he was        Anyway  if your teacher is the same  here is the hard way to do it    std  string LongToString long value      std  string output    std  string sign     if value  lt  0          sign    -       value   -value         while output empty       value  gt  0           output push front value   10    0       value    10         return sign   output      You could argue that using std  string is not  the hard way   but I guess what counts in the actual agorithm

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One of the things not covered by anybody so far  to help you think about the problem further  is what format should a long take when it is cast to a string   Just have a look at a spreedsheet program  like Calc Excel    Do you want it rounded to the nearest million  with brackets if it s negative  always to show the sign     Is the number realy a representation of something else  should you show it in Oractal or Hex instead   The answers so far have given you some default output  but perhaps not the right ones

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There are several ways   Read The String Formatters of Manor Farm for an in-depth comparison

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int main         long mylong   123456789      string mystring      stringstream mystream      mystream  lt  lt  mylong      mystring   mystream str        cout  lt  lt  mystring  lt  lt    n       return 0

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Check out std  stringstream

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include  lt sstream gt                 std  stringstream ss      ss  lt  lt  a long int      or any other type     std  string result ss str         use  str   to get a string back

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You could use stringstream    include  lt sstream gt          std  string number  std  stringstream strstream  strstream  lt  lt  1L  strstream  gt  gt  number    There is usually some proprietary C functions in the standard library for your compiler that does it too  I prefer the more  portable  variants though   The C way to do it would be with sprintf  but that is not very secure  In some libraries there is new versions like sprintf s which protects against buffer overruns

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In C  11  there are actually std  to string and std  to wstring functions in  lt string gt    string to string int val   string to string long val   string to string long long val   string to string unsigned val   string to string unsigned long val   string to string unsigned long long val   string to string float val   string to string double val   string to string  long double val

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Well if you are fan of copy-paste  here it is    include  lt sstream gt   template  lt class T gt  inline std  string to string  const T amp  t        std  stringstream ss      ss  lt  lt  t      return ss str

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You can use std  to string in C  11  long val   12345  std  string my val   std  to string val

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The way I typically do it is with sprintf  So for a long you could do the following assuming that you are on a 32 bit architecture   char buf 5     0      one extra byte for null     sprintf buf    l   var for long

[c++] How do I convert a long to a string in C++?

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